In the past, an apparatus which classifies a type of a defect at a semiconductor wafer using an image of the same has been proposed (see Patent Citation 1). This apparatus captures an image of a semiconductor wafer (object under inspection), analyzes the obtained image, and classifies the defect etc. of the semiconductor wafer appearing in that image. Specifically, it converts a plurality of parameters expressing the shape, color, image luminance, and other features of a defect appearing in the image into numerical values to generate a vector defined by the set of the plurality of parameters as a feature vector expressing the features of the defect. Further, it classifies a defect included in the image based on the position of a point in a feature space corresponding to that feature vector (feature point).
According to such a feature analysis apparatus, designed to analyze image data expressing an image (inspected object) (inspected object information: for example, luminance values of pixel units) so as to obtain a feature vector expressing the features of the image, it becomes possible for example to classify a defect or other inspected object of a semiconductor wafer based on the feature vector.    Patent Citation 1: Japanese Patent Publication (A) No. 2001-256480